The effect of exogenous calcium on cucumber fruit quality, photosynthesis, chlorophyll fluorescence, and fast chlorophyll fluorescence during the fruiting period under hypoxic stress

Abstract

BackgroundPlants often suffer from hypoxic stress during waterlogging and hydroponic culturing. This study investigated the response of cucumber (Cucumis sativus L.) plant growth parameters, leaf photosynthesis, chlorophyll fluorescence, fast chlorophyll a fluorescence transient (OJIP), and fruit quality parameters to hypoxic stress alleviated by exogenous calcium. During the fruiting period, cucumber plants were exposed to hypoxia and hypoxia + Ca2+ treatment (4 mM Ca2+) for 9 d.ResultExogenous calcium application enhanced the biomass and fruit quality of hypoxic stressed cucumber and also increased the net photosynthesis rate, stomatal conductance, intercellular CO2 concentration, maximum quantum efficiency of photosystem II photochemistry, actual photochemical efficiency of PSII, photochemical quenching coefficient, and non-photochemical quenching coefficient. Additionally, measurement of chlorophyll a fluorescence transients showed the positive K- and L-bands were more pronounced in leaves treated with hypoxia compared with those with hypoxia + Ca2+, indicating that hypoxic treatment induced uncoupling of the oxygen-evolving complex and inhibited electron transport beyond plastoquinone pool (Qa, Qb) including possible constraints on the reduction of end electron acceptors of photosystem I. Exogenous calcium can reduce these stress-induced damages in cucumber.ConclusionThis research focused the effect of exogenous calcium on cucumber photosynthesis during the fruiting period under hypoxic stress. Hypoxic stress might impair the photosynthetic electron-transport chain from the donor side of PSII up to the reduction of end acceptors of PSI, and exogenous calcium enhanced electron transport capacity and reduced hypoxic damage of cucumber leaves.

Quality attributes and related enzyme activities in peppers during storage: effect of hydrothermal and calcium chloride treatment

“…According to Figure 3, the chlorophyll contents in CaCl 2 -treated peppers were the most comparing other treatments during storage. He et al [30] also found that CaCl 2 treatment reduced the hypoxic damage of cucumber leaves and enhanced the stability of chlorophylls. However, HT and HT-CaCl 2 treatments were related to temperature, and chlorophylls are sensitive to temperature, which accelerated chlorophylls degradation in some extent.…”

Supplementary Calcium Restores Peanut (Arachis hypogaea) Growth and Photosynthetic Capacity Under Low Nocturnal Temperature

“…Calcium, an essential element for plants, serves not only as a structural component in plant cells but also as a key signaling molecule involved in multiple signal-transduction pathways in its ionic form Ca 2+ (White and Broadley, 2003;Tian et al, 2019). In particular, calcium has well-documented roles in mediating plant responses to abiotic and biotic stimuli (Cachorro et al, 1994;Skórzyńska-Polit et al, 1998;White and Broadley, 2003;Ding et al, 2018;He et al, 2018;Naeem et al, 2018;Patrick et al, 2018). Low-temperature stress often leads to an increase in free Ca 2+ in plants, followed by cold-induced protein phosphorylation and the accumulation of the cold acclimationspecific genes that improve the adaptation of plants to cold stress (Monroy and Dhindsa, 1995).…”

Physiological, Biochemical and Chlorophyll Fluorescence Parameters of Physalis Peruviana L. Seedlings Exposed to Different Short-Term Waterlogging Periods and Fusarium Wilt Infection

“…Kallestad et al [25] also found similar effects in pecan tree (Carya illinoinensis) seedlings. On the other hand, chlorophyll fluorescence parameters have been widely used as indicators of the photosystem II (PSII) activity under soil oxygen deficiency conditions [26,27]. Ren et al [23] found a reduction of 16% in the F v /F m and Y (II) values in two maize (Zea mays L.) hybrids under short waterlogging periods (6 d).…”